<img src="https://place-hold.it/280x220?text=280%C3%97220&fontsize=33"
  srcset="https://place-hold.it/280x220?text=280%C3%97220&fontsize=33 280w,
          https://place-hold.it/560x440?text=560%C3%97440&fontsize=33 560w,
          https://place-hold.it/840x660?text=840%C3%97660&fontsize=33 840w"
  sizes="100vw">
